DAQ-2024-007696

DAQE-AN103670029-24

{{$d1 }}

Stewart Hogan
Asahi Refining USA, Incorporated
4601 West 2100 South
West Valley City, UT 84120
[e-mail]

Dear Mr. Hogan:

Re: Approval Order: Modification to Approval Order DAQE-AN103670028-17A to Replace
Equipment
Project Number: N103670029

The attached Approval Order (AO) is issued pursuant to the Notice of Intent (NOI) received on January
16, 2024. Asahi Refining USA, Incorporated must comply with the requirements of this AO, all
applicable state requirements (R307), and Federal Standards.

The project engineer for this action is Christine Bodell, who can be contacted at [phone] or
[e-mail]. Future correspondence on this AO should include the engineer's name as well as the
DAQE number shown on the upper right-hand corner of this letter. No public comments were received
on this action.

Sincerely,

{{$s }}

Bryce C. Bird
Director

BCB:CB:jg

cc: Salt Lake County Health Department

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor

DEIDRE HENDERSON
Lieutenant Governor

Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF AIR QUALITY
Bryce C. Bird
Director

April 4, 2024

STATE OF UTAH
Department of Environmental Quality
Division of Air Quality

{{#s=Sig_es_:signer1:signature}}
{{#d1=date1_es_:signer1:date:format(date, "mmmm d, yyyy")}}
{{#d2=date1_es_:signer1:date:format(date, "mmmm d, yyyy"):align(center)}}

APPROVAL ORDER
DAQE-AN103670029-24
Modification to Approval Order DAQE-AN103670028-17A to
Replace Equipment

Prepared By
Christine Bodell, Engineer
[phone]
[e-mail]

Issued to
Asahi Refining USA, Incorporated

Issued On
{{$d2 }}

Issued By

{{$s }}

Bryce C. Bird
Director
Division of Air Quality

April 4, 2024
TABLE OF CONTENTS

TITLE/SIGNATURE PAGE ....................................................................................................... 1
GENERAL INFORMATION ...................................................................................................... 3
CONTACT/LOCATION INFORMATION ............................................................................... 3
SOURCE INFORMATION ........................................................................................................ 3
General Description ................................................................................................................ 3
NSR Classification .................................................................................................................. 3
Source Classification .............................................................................................................. 3
Applicable Federal Standards ................................................................................................. 3
Project Description.................................................................................................................. 4
SUMMARY OF EMISSIONS .................................................................................................... 4
SECTION I: GENERAL PROVISIONS .................................................................................... 4
SECTION II: PERMITTED EQUIPMENT .............................................................................. 5
SECTION II: SPECIAL PROVISIONS ..................................................................................... 7
PERMIT HISTORY ................................................................................................................... 10
ACRONYMS ............................................................................................................................... 11

DAQE-AN103670029-24
Page 3

GENERAL INFORMATION

CONTACT/LOCATION INFORMATION

Owner Name Source Name
Asahi Refining USA, Incorporated Asahi Refining USA, Incorporated

Mailing Address Physical Address
4601 West 2100 South 4601 West 2100 South
West Valley City, UT 84120 West Valley City, UT 84120

Source Contact UTM Coordinates
Name: Stewart Hogan 415,495 m Easting
Phone: [phone],508,700 m Northing
Email: [e-mail] Datum NAD83
UTM Zone 12

SIC code 3339 (Primary Smelting & Refining of Nonferrous Metals, Except Copper & Aluminum)

SOURCE INFORMATION
General Description
Asahi Refining USA, Incorporated (Asahi) currently operates a precious metals refinery in West Valley
City, Salt Lake County. Mined doré and scrap are melted and tested for purity using small electric
induction furnaces, and then separated depending on gold and silver content. Separation is achieved by
using various inorganic chemicals and electrolytic methods. Silver is poured into anode molds and then
placed into the electrolytic cells. The cells contain silver nitrate solution, and the low voltage current
causes silver crystal to form onto a cathode plate. The silver crystal is scraped off and collected.

NSR Classification
Minor Modification at Minor Source

Source Classification
Located in Northern Wasatch Front O3 NAA, Salt Lake City UT PM2.5 NAA, Salt Lake County SO2
NAA
Salt Lake County
Airs Source Size: B

Applicable Federal Standards
MACT (Part 63), A: General Provisions
MACT (Part 63), ZZZZ: National Emissions Standards for Hazardous Air Pollutants for
Stationary Reciprocating Internal Combustion Engines
DAQE-AN103670029-24
Page 4

Project Description
Asahi has requested a modification to AO DAQE-AN103670028-17A to replace the silver electrolytic
cells (Equipment ID II.A.3 in Approval Order DAQE-AN103670028-17A). The NOx emissions from the
new silver electrolytic cells will be controlled with a new scrubber (Scrubber ID 761). The scrubber
currently servicing the existing silver electrolytic cells (Equipment ID II.A.23, Scrubber 760) will be
retained and will continue to control other existing processes. The NOx and SO2 emission limitations
outlined in the current AO will not be increasing as part of this modification. The new equipment will
operate under existing emissions limitations.

SUMMARY OF EMISSIONS

The emissions listed below are an estimate of the total potential emissions from the source. Some
rounding of emissions is possible.

Criteria Pollutant Change (TPY) Total (TPY)
Ammonia 0 0.06
CO2 Equivalent 0 994.70
Carbon Monoxide 0 0.73
Lead 0 0.01
Nitrogen Oxides 0 4.31
Particulate Matter - PM10 0 2.01
Particulate Matter - PM2.5 0 2.01
Sulfur Dioxide 0 6.11
Volatile Organic Compounds 0 0.09

Hazardous Air Pollutant Change (lbs/yr) Total (lbs/yr)
Chlorine (CAS #7782505) 0 800
Hexane (CAS #110543) 0 20
Hydrochloric Acid (Hydrogen Chloride) (CAS #7647010) 0 1600
Lead (CAS #7439921) 0 20
Selenium & Compounds (CAS #253) 0 60
Change (TPY) Total (TPY)
Total HAPs 0 1.25

SECTION I: GENERAL PROVISIONS

I.1 All definitions, terms, abbreviations, and references used in this AO conform to those used in
the UAC R307 and 40 CFR. Unless noted otherwise, references cited in these AO conditions
refer to those rules. [R307-101]

I.2 The limits set forth in this AO shall not be exceeded without prior approval. [R307-401]

DAQE-AN103670029-24
Page 5

I.3 Modifications to the equipment or processes approved by this AO that could affect the
emissions covered by this AO must be reviewed and approved. [R307-401-1]

I.4 All records referenced in this AO or in other applicable rules, which are required to be kept by
the owner/operator, shall be made available to the Director or Director's representative upon
request, and the records shall include the two-year period prior to the date of the request.
Unless otherwise specified in this AO or in other applicable state and federal rules, records
shall be kept for a minimum of two (2) years. [R307-401-8]

I.5 At all times, including periods of startup, shutdown, and malfunction, owners and operators
shall, to the extent practicable, maintain and operate any equipment approved under this AO,
including associated air pollution control equipment, in a manner consistent with good air
pollution control practice for minimizing emissions. Determination of whether acceptable
operating and maintenance procedures are being used will be based on information available to
the Director which may include, but is not limited to, monitoring results, opacity observations,
review of operating and maintenance procedures, and inspection of the source. All
maintenance performed on equipment authorized by this AO shall be recorded. [R307-401-4]

I.6 The owner/operator shall comply with UAC R307-107. General Requirements: Breakdowns.
[R307-107]

I.7 The owner/operator shall comply with UAC R307-150 Series. Emission Inventories.
[R307-150]

I.8 The owner/operator shall submit documentation of the status of construction or modification to
the Director within 18 months from the date of this AO. This AO may become invalid if
construction is not commenced within 18 months from the date of this AO or if construction is
discontinued for 18 months or more. To ensure proper credit when notifying the Director, send
the documentation to the Director, attn.: NSR Section. [R307-401-18]

SECTION II: PERMITTED EQUIPMENT

II.A THE APPROVED EQUIPMENT

II.A.1 Metal Refinery
Precious Metals Refinery Plant.

II.A.2 Wastewater Treatment
Wastewater effluent treatment. Process controlled by scrubber #760.

II.A.3 Electrolytic Cells (New)
Silver electrolytic cell (refining of silver). Process controlled by scrubber #761.

II.A.4 Electrolytic Cells
Gold electrolytic cell (refining of gold). Process controlled by scrubber #359.

II.A.5 Wet Circuit
Gold refinery wet circuits (part of the gold refining process). Process controlled by scrubber
#359.

II.A.6 Chlorination
Gold chloride electrolytic production (refining of gold). Process controlled by scrubber #359.

DAQE-AN103670029-24
Page 6

II.A.7 Slime Washing
Silver anode slime washing process (recovery of gold). Process controlled by scrubber #248.

II.A.8 Wet Chlorides Treatment
Hydrometallurgical process for silver chlorides sludge processing (recovery of gold). Controlled
by scrubber #359.

II.A.9 Fabric-Filter Baghouse
Four (4) fabric-filter baghouses

One (1) baghouse controls emissions from the sweeps preparation process. Two (2) baghouses
control emissions from the melt room furnaces, the electric tilt furnaces, and the electric push -out
furnaces. One (1) baghouse controls the ashing furnace (Item II.A.26).

II.A.10 Boiler
One (1) boiler, natural gas-fueled, rated less than 5 MMBtu/hr.

II.A.11 Dust Collector
Dust collector for welding fume and grinding dust control in maintenance shop.

II.A.12 Electrostatic Precipitator
One (1) wet-electrostatic precipitator (ID: WESP II).

II.A.13 Chlorination Furnaces
Four (4) electric-induction chlorination furnaces. Process controlled by venturi scrubber, WESP
II, and scrubber #359.

II.A.14 Melt Furnaces
Three (3) melt-room furnaces, natural gas-fueled, rated less than 5 MMBtu/hr each. Process
controlled by a nanofilter baghouse made by UAS or the combination of the venturi scrubber,
WESP II, and scrubber #359.

II.A.15 Tilt Furnaces
Seven (7) electric-tilt furnaces. Process controlled by a nanofilter baghouse made by UAS or the
combination of the venturi scrubber, WESP II, and scrubber #359.

II.A.16 Push-out Furnaces
Four (4) electric push-out furnaces. Process controlled by baghouse or the combination of the
venturi scrubber, WESP II, and scrubber #359.

II.A.17 Emergency Generator Engine
One (1) emergency power generator engine, natural gas-fueled, rated at 60 kW

II.A.18 Combustion Afterburner
One (1) incinerator, natural gas-fueled, rated less than 5 MMBtu/hr

II.A.19 Nitrate Plant
Silver nitrate plant (recovery of silver). Process controlled by scrubber #248.

II.A.20 Slime Plant
Slime plant (recovery of gold). Process controlled by scrubber #248.

II.A.21 Drying Cabinets
Five (5) electric drying cabinets. Process controlled by the combination of the venturi scrubber,
WESP II, and scrubber #359.

DAQE-AN103670029-24
Page 7

II.A.22 Drying Cabinet
One (1) drying cabinet, natural gas-fueled, rated less than 5 MMBtu/hr.

II.A.23 Wet Scrubbers
Four (4) packed bed wet scrubbers (ID: 760, 359, 248, 761 (New)).

II.A.24 Venturi Scrubber
One (1) venturi scrubber attached to WESP II as a pre-scrubber.

II.A.25 Tank System
Silver reduction tanks (recovery of silver). Process controlled by scrubber #248.

II.A.26 Ashing Furnace
One (1) dental scrap ashing furnace. Process controlled by baghouse (Item II.A.9) and activated
carbon adsorption system (Item II.A.27).

II.A.27 Activated Carbon Adsorption System
One (1) activated carbon adsorption system controls the ashing furnace (Item II.A.26)

SECTION II: SPECIAL PROVISIONS

II.B REQUIREMENTS AND LIMITATIONS

II.B.1 Site-Wide Requirements
II.B.1.a The owner/operator shall not allow visible emissions from the following emission points to
exceed the following values:

A. All fabric filter baghouse exhaust stacks - 10%

B. All electrostatic precipitator exhaust stacks - 10%

C. All scrubber exhaust stacks - 10%

D. All incinerator exhaust stacks - 10%

E. All boiler exhaust stacks - 10%

F. All other points - 20%

[R307-401-8]

II.B.1.a.1 Opacity observations of emissions from stationary sources shall be conducted according to 40
CFR 60, Appendix A, Method 9. [R307-401-8]

II.B.1.b The owner/operator shall not produce more than the following:

A. 12,000,000 troy ounces of gold per rolling 12-month period.

B. 60,000,000 troy ounces of silver per rolling 12-month period.

C. 400 tons of sweeps per rolling 12-month period.

[R307-401-8]

DAQE-AN103670029-24
Page 8

II.B.1.b.1 The owner/operator shall:

A. Determine gold, silver, and sweeps production by company production records.

B. Record gold and silver production on a daily basis and record sweeps production
on a monthly basis.

C. Use the gold and silver production data to calculate a new rolling 12-month total
by the 20th day of each month using data from the previous 12 months.

D. Use the sweeps production data to calculate a new rolling 12-month total by the
20th day of January, April, July, and October of each year using data from the
previous 12 months.

E. Keep the gold, silver, and sweeps production records for all periods the plant is
in operation.

[R307-401-8]

II.B.2 Baghouse Requirements
II.B.2.a The owner/operator shall use baghouses to control particulate emissions from the sweeps
preparation process, melt room furnaces, electric tilt furnaces, electric push-out furnaces, and the
ashing furnace. [R307-401-8]

II.B.2.b The owner/operator shall install a manometer or magnehelic pressure gauge to measure the static
pressure differential across each baghouse. [R307-401-8]

II.B.2.b.1 The pressure gauge shall be located such that an inspector/operator can safely read the indicator
at any time. [R307-401-8]

II.B.2.b.2 The pressure gauge shall measure the static pressure differential in 1-inch water column
increments or less. [R307-401-8]

II.B.2.c During operation of each baghouse, the owner/operator shall maintain the static pressure
differential within the range recommended by the manufacturer for normal operations.
[R307-401-8]

II.B.2.c.1 The owner/operator shall record the static pressure differential at least once per operating day
while each baghouse is operating. [R307-401-8]

II.B.2.c.2 The owner/operator shall maintain the following records of the static pressure differential:

A. Unit identification;

B. Manufacturer recommended static pressure differential range for the unit;

C. Daily static pressure differential readings;

D. Date of reading.

[R307-401-8]

II.B.2.d At least once every 12 months, the owner/operator shall calibrate each pressure gauge in
accordance with the manufacturer's instructions or replace the pressure gauge. [R307-401-8]

II.B.2.d.1 The owner/operator shall maintain records of each pressure gauge calibrations and replacements.
[R307-401-8]

DAQE-AN103670029-24
Page 9

II.B.3 Emergency Engine Requirements
II.B.3.a The owner/operator shall not operate the emergency engine on site for more than 100 hours per
rolling 12-month period during non-emergency situations. There is no time limit on the use of
the engine during emergencies. [40 CFR 63 Subpart ZZZZ, R307-401-8]

II.B.3.a.1 To determine compliance with a rolling 12-month total, the owner/operator shall calculate a new
12-month total by the 20th day of each month using data from the previous 12 months. Records
documenting the operation of the emergency engine shall be kept in a log and shall include the
following:

A. The date the emergency engine was used.

B. The duration of operation in hours.

C. The reason for the emergency engine usage.

[40 CFR 63 Subpart ZZZZ, R307-401-8]

II.B.3.b The owner/operator shall only use natural gas as fuel in the emergency engine. [R307-401-8]

II.B.4 Wet Scrubber Requirements
II.B.4.a The owner/operator shall use the following scrubbers to control the following process streams.

Scrubber Process Stream
Scrubber #248 silver anode slime washing process, silver nitrate plant, and slime
plant

Scrubber #359 gold electrolytic cells, gold refinery wet circuits, gold chloride
electrolytic production, silver chlorides sludge processing,
chlorination furnaces, melt furnaces, tilt furnaces, push-out
furnaces, and drying cabinets

Scrubber #760 wastewater treatment tanks and laboratory

Scrubber #761 silver electrolytic cells

All exhaust air from the above-mentioned process streams shall be routed through the indicated
scrubber before being vented to the atmosphere.

[R307-401-8]

II.B.4.b During operation of each scrubber, the owner/operator shall maintain both the pressure drop and
the liquid flow rate within the respective range recommended by the manufacturer for normal
operations. [R307-401-8]

II.B.4.b.1 The parameters shall be monitored with instruments located such that an inspector/operator can
safely read the output any time. [R307-401-8]

II.B.4.c The owner/operator shall record both the pressure drop and liquid flow rate at least once per
operating day while each scrubber is operating. [R307-401-8]

DAQE-AN103670029-24
Page 10

II.B.4.c.1 The owner/operator shall maintain the following records of the pressure drop and liquid flow
rate:

A. Unit identification;

B. Manufacturer recommended pressure drop and liquid flow rate range;

C. Daily pressure drop and liquid flow rate readings;

D. Date of reading.

[R307-401-8]

II.B.4.d At least once every 12 months, the owner/operator shall calibrate each instrument in accordance
with the manufacturer's instructions or replace the instrument. [R307-401-8]

II.B.4.d.1 The owner/operator shall maintain records of each instrument calibrations and replacements.
[R307-401-8]

II.B.4.e The owner/operator shall install a scrubber (ID# 761) that is certified to meet a NOx emission
reduction of no less than 24%. [R307-401-8]

II.B.4.e.1 To demonstrate compliance with the above condition, the owner/operator shall maintain records
of the manufacturer's emissions guarantee for the installed scrubber. [R307-401-8]

PERMIT HISTORY

This Approval Order shall supersede (if a modification) or will be based on the following documents:

Supersedes AO DAQE-AN103670028-17A dated May 15, 2017
Is Derived From NOI dated January 16, 2024

DAQE-AN103670029-24
Page 11

ACRONYMS

The following lists commonly used acronyms and associated translations as they apply to this document:

40 CFR Title 40 of the Code of Federal Regulations
AO Approval Order
BACT Best Available Control Technology
CAA Clean Air Act
CAAA Clean Air Act Amendments
CDS Classification Data System (used by Environmental Protection Agency to classify
sources by size/type)
CEM Continuous emissions monitor
CEMS Continuous emissions monitoring system
CFR Code of Federal Regulations
CMS Continuous monitoring system
CO Carbon monoxide
CO2 Carbon Dioxide
CO2e Carbon Dioxide Equivalent - Title 40 of the Code of Federal Regulations Part 98,
Subpart A, Table A-1
COM Continuous opacity monitor
DAQ/UDAQ Division of Air Quality
DAQE This is a document tracking code for internal Division of Air Quality use
EPA Environmental Protection Agency
FDCP Fugitive dust control plan
GHG Greenhouse Gas(es) - Title 40 of the Code of Federal Regulations 52.21 (b)(49)(i)
GWP Global Warming Potential - Title 40 of the Code of Federal Regulations Part 86.1818-
12(a)
HAP or HAPs Hazardous air pollutant(s)
ITA Intent to Approve
LB/YR Pounds per year
MACT Maximum Achievable Control Technology
MMBTU Million British Thermal Units
NAA Nonattainment Area
NAAQS National Ambient Air Quality Standards
NESHAP National Emission Standards for Hazardous Air Pollutants
NOI Notice of Intent
NOx Oxides of nitrogen
NSPS New Source Performance Standard
NSR New Source Review
PM10 Particulate matter less than 10 microns in size
PM2.5 Particulate matter less than 2.5 microns in size
PSD Prevention of Significant Deterioration
PTE Potential to Emit
R307 Rules Series 307
R307-401 Rules Series 307 - Section 401
SO2 Sulfur dioxide
Title IV Title IV of the Clean Air Act
Title V Title V of the Clean Air Act
TPY Tons per year
UAC Utah Administrative Code
VOC Volatile organic compounds

DAQE-IN103670029-24

February 29, 2024

Stewart Hogan
Asahi Refining USA, Incorporated
4601 West 2100 South
West Valley City, UT 84120
[e-mail]

Dear Mr. Hogan:

Re: Intent to Approve: Modification to Approval Order DAQE-AN103670028-17A to Replace
Equipment
Project Number: N103670029

The attached document is the Intent to Approve (ITA) for the above-referenced project. The ITA is
subject to public review. Any comments received shall be considered before an Approval Order (AO) is
issued. The Division of Air Quality is authorized to charge a fee for reimbursement of the actual costs
incurred in the issuance of an AO. An invoice will follow upon issuance of the final AO.

Future correspondence on this ITA should include the engineer's name, Christine Bodell, as well as the
DAQE number as shown on the upper right-hand corner of this letter. Christine Bodell, can be reached at
[phone] or [e-mail], if you have any questions.

Sincerely,

{{$s }}

Alan D. Humpherys, Manager
New Source Review Section

ADH:CB:jg

cc: Salt Lake County Health Department

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor

DEIDRE HENDERSON
Lieutenant Governor

Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF AIR QUALITY
Bryce C. Bird
Director

STATE OF UTAH
Department of Environmental Quality
Division of Air Quality

INTENT TO APPROVE
DAQE-IN103670029-24
Modification to Approval Order DAQE-AN103670028-17A
to Replace Equipment

Prepared By
Christine Bodell, Engineer
[phone]
[e-mail]

Issued to
Asahi Refining Incorporated

Issued On
February 29, 2024

{{$s }}

New Source Review Section Manager
Alan D. Humpherys
{{#s=Sig_es_:signer1:signature}}

TABLE OF CONTENTS

TITLE/SIGNATURE PAGE ....................................................................................................... 1
GENERAL INFORMATION ...................................................................................................... 3
CONTACT/LOCATION INFORMATION ............................................................................... 3
SOURCE INFORMATION ........................................................................................................ 3
General Description ................................................................................................................ 3
NSR Classification .................................................................................................................. 3
Source Classification .............................................................................................................. 3
Applicable Federal Standards ................................................................................................. 3
Project Description.................................................................................................................. 4
SUMMARY OF EMISSIONS .................................................................................................... 4
PUBLIC NOTICE STATEMENT............................................................................................... 4
SECTION I: GENERAL PROVISIONS .................................................................................... 5
SECTION II: PERMITTED EQUIPMENT .............................................................................. 6
SECTION II: SPECIAL PROVISIONS ..................................................................................... 8
PERMIT HISTORY ................................................................................................................... 11
ACRONYMS ............................................................................................................................... 12

DAQE-IN103670029-24
Page 3

GENERAL INFORMATION

CONTACT/LOCATION INFORMATION

Owner Name Source Name
Asahi Refining USA, Incorporated Asahi Refining Incorporated

Mailing Address Physical Address
4601 West 2100 South 4601 West 2100 South
West Valley City, UT 84120 West Valley City, UT 84120

Source Contact UTM Coordinates
Name: Stewart Hogan 415,495 m Easting
Phone: [phone],508,700 m Northing
Email: [e-mail] Datum NAD83
UTM Zone 12

SIC code 3339 (Primary Smelting & Refining of Nonferrous Metals, Except Copper & Aluminum)

SOURCE INFORMATION
General Description
Asahi Refining USA, Incorporated (Asahi) currently operates a precious metals refinery in West Valley
City, Salt Lake County. Mined doré and scrap are melted and tested for purity using small electric
induction furnaces and then separated depending on gold and silver content. Separation is achieved by
using various inorganic chemicals and electrolytic methods. Silver is poured into anode molds and then
placed into the electrolytic cells. The cells contain silver nitrate solution, and the low voltage current
causes silver crystal to form onto a cathode plate. The silver crystal is scraped off and collected.
NSR Classification
Minor Modification at Minor Source

Source Classification
Located in Northern Wasatch Front O3 NAA, Salt Lake City UT PM2.5 NAA, Salt Lake County SO2
NAA
Salt Lake County
Airs Source Size: B

Applicable Federal Standards
MACT (Part 63), A: General Provisions
MACT (Part 63), ZZZZ: National Emissions Standards for Hazardous Air Pollutants for
Stationary Reciprocating Internal Combustion Engines
DAQE-IN103670029-24
Page 4

Project Description
Asahi has requested a modification to AO DAQE-AN103670028-17A to replace the silver electrolytic
cells (Equipment ID II.A.3 in Approval Order DAQE-AN103670028-17A). The NOx emissions from the
new silver electrolytic cells will be controlled with a new scrubber (Scrubber ID 761). The scrubber
currently servicing the existing silver electrolytic cells (Equipment ID II.A.23 - Scrubber 760) will be
retained and will continue to control other, existing processes. The NOx and SO2 emission limitations
outlined in the current AO will not be increasing as part of this modification. The new equipment will
operate under existing emissions limitations.

SUMMARY OF EMISSIONS

The emissions listed below are an estimate of the total potential emissions from the source. Some
rounding of emissions is possible.

Criteria Pollutant Change (TPY) Total (TPY)
Ammonia 0 0.06
CO2 Equivalent 0 994.70
Carbon Monoxide 0 0.73
Lead 0 0.01
Nitrogen Oxides 0 4.31
Particulate Matter - PM10 0 2.01
Particulate Matter - PM2.5 0 2.01
Sulfur Dioxide 0 6.11
Volatile Organic Compounds 0 0.09

Hazardous Air Pollutant Change (lbs/yr) Total (lbs/yr)
Chlorine (CAS #7782505) 0 800
Hexane (CAS #110543) 0 20
Hydrochloric Acid (Hydrogen Chloride) (CAS #7647010) 0 1600
Lead (CAS #7439921) 0 20
Selenium & Compounds (CAS #253) 0 60
Change (TPY) Total (TPY)
Total HAPs 0 1.25

PUBLIC NOTICE STATEMENT

The NOI for the above-referenced project has been evaluated and has been found to be consistent with the
requirements of UAC R307. Air pollution producing sources and/or their air control facilities may not be
constructed, installed, established, or modified prior to the issuance of an AO by the Director.

A 30-day public comment period will be held in accordance with UAC R307-401-7. A notification of the
intent to approve will be published in the Salt Lake Tribune and Deseret News on March 3, 2024. During
the public comment period the proposal and the evaluation of its impact on air quality will be available
for the public to review and provide comment. If anyone so requests a public hearing within 15 days of
publication, it will be held in accordance with UAC R307-401-7. The hearing will be held as close as
practicable to the location of the source. Any comments received during the public comment period and
the hearing will be evaluated. The proposed conditions of the AO may be changed as a result of the
comments received.
DAQE-IN103670029-24
Page 5

SECTION I: GENERAL PROVISIONS

The intent is to issue an air quality AO authorizing the project with the following recommended
conditions and that failure to comply with any of the conditions may constitute a violation of the AO.

I.1 All definitions, terms, abbreviations, and references used in this AO conform to those used in
the UAC R307 and 40 CFR. Unless noted otherwise, references cited in these AO conditions
refer to those rules. [R307-101]

I.2 The limits set forth in this AO shall not be exceeded without prior approval. [R307-401]

I.3 Modifications to the equipment or processes approved by this AO that could affect the
emissions covered by this AO must be reviewed and approved. [R307-401-1]

I.4 All records referenced in this AO or in other applicable rules, which are required to be kept by
the owner/operator, shall be made available to the Director or Director's representative upon
request, and the records shall include the two-year period prior to the date of the request.
Unless otherwise specified in this AO or in other applicable state and federal rules, records
shall be kept for a minimum of two (2) years. [R307-401-8]

I.5 At all times, including periods of startup, shutdown, and malfunction, owners and operators
shall, to the extent practicable, maintain and operate any equipment approved under this AO,
including associated air pollution control equipment, in a manner consistent with good air
pollution control practice for minimizing emissions. Determination of whether acceptable
operating and maintenance procedures are being used will be based on information available to
the Director which may include, but is not limited to, monitoring results, opacity observations,
review of operating and maintenance procedures, and inspection of the source. All
maintenance performed on equipment authorized by this AO shall be recorded. [R307-401-4]

I.6 The owner/operator shall comply with UAC R307-107. General Requirements: Breakdowns.
[R307-107]

I.7 The owner/operator shall comply with UAC R307-150 Series. Emission Inventories.
[R307-150]

I.8 The owner/operator shall submit documentation of the status of construction or modification to
the Director within 18 months from the date of this AO. This AO may become invalid if
construction is not commenced within 18 months from the date of this AO or if construction is
discontinued for 18 months or more. To ensure proper credit when notifying the Director, send
the documentation to the Director, attn.: NSR Section. [R307-401-18]

DAQE-IN103670029-24
Page 6

SECTION II: PERMITTED EQUIPMENT

The intent is to issue an air quality AO authorizing the project with the following recommended
conditions and that failure to comply with any of the conditions may constitute a violation of the AO.

II.A THE APPROVED EQUIPMENT

II.A.1 Metal Refinery
Precious Metals Refinery Plant

II.A.2 Wastewater Treatment
Wastewater effluent treatment. Process controlled by scrubber #760

II.A.3 Electrolytic Cells (New)
Silver electrolytic cell (refining of silver). Process controlled by scrubber #761.

II.A.4 Electrolytic Cells
Gold electrolytic cell (refining of gold). Process controlled by scrubber #359.

II.A.5 Wet Circuit
Gold refinery wet circuits (part of the gold refining process). Process controlled by scrubber
#359.

II.A.6 Chlorination
Gold chloride electrolytic production (refining of gold). Process controlled by scrubber #359.

II.A.7 Slime Washing
Silver anode slime washing process (recovery of gold). Process controlled by scrubber #248.

II.A.8 Wet Chlorides Treatment
Hydrometallurgical process for silver chlorides sludge processing (recovery of gold). Controlled
by scrubber #359.

II.A.9 Fabric-Filter Baghouse
Four (4) fabric-filter baghouses

One (1) baghouse controls emissions from the sweeps preparation process. Two (2) baghouses
control emissions from the melt room furnaces, the electric tilt furnaces, and the electric push -out
furnaces. One (1) baghouse controls the ashing furnace (Item II.A.26).

II.A.10 Boiler
One (1) boiler, natural gas-fueled, rated less than 5 MMBtu/hr

II.A.11 Dust Collector
Dust collector for welding fume and grinding dust control in maintenance shop

II.A.12 Electrostatic Precipitator
One (1) wet-electrostatic precipitator (ID: WESP II)

II.A.13 Chlorination Furnaces
Four (4) electric-induction chlorination furnaces. Process controlled by venturi scrubber, WESP
II, and scrubber #359.

DAQE-IN103670029-24
Page 7

II.A.14 Melt Furnaces
Three (3) melt-room furnaces, natural gas-fueled, rated less than 5 MMBtu/hr each. Process
controlled by a nanofilter baghouse made by UAS or the combination of the venturi scrubber,
WESP II, and scrubber #359.

II.A.15 Tilt Furnaces
Seven (7) electric-tilt furnaces. Process controlled by a nanofilter baghouse made by UAS or the
combination of the venturi scrubber, WESP II, and scrubber #359.

II.A.16 Push-out Furnaces
Four (4) electric push-out furnaces. Process controlled by baghouse or the combination of the
venturi scrubber, WESP II, and scrubber #359.

II.A.17 Emergency Generator Engine
One (1) emergency power generator engine, natural gas-fueled, rated at 60 kW.

II.A.18 Combustion Afterburner
One (1) incinerator, natural gas-fueled, rated less than 5 MMBtu/hr

II.A.19 Nitrate Plant
Silver nitrate plant (recovery of silver). Process controlled by scrubber #248.

II.A.20 Slime Plant
Slime plant (recovery of gold). Process controlled by scrubber #248.

II.A.21 Drying Cabinets
Five (5) electric drying cabinets. Process controlled by the combination of the venturi scrubber,
WESP II, and scrubber #359.

II.A.22 Drying Cabinet
One (1) drying cabinet, natural gas-fueled, rated less than 5 MMBtu/hr.

II.A.23 Wet Scrubbers
Four (4) packed bed wet scrubbers (ID: 760, 359, 248, 761 (New)).

II.A.24 Venturi Scrubber
One (1) venturi scrubber attached to WESP II as a pre-scrubber.

II.A.25 Tank System
Silver reduction tanks (recovery of silver). Process controlled by scrubber #248.

II.A.26 Ashing Furnace
One (1) dental scrap ashing furnace. Process controlled by baghouse (Item II.A.9) and activated
carbon adsorption system (Item II.A.27).

II.A.27 Activated Carbon Adsorption System
One (1) activated carbon adsorption system controls the ashing furnace (Item II.A.26)

DAQE-IN103670029-24
Page 8

SECTION II: SPECIAL PROVISIONS

The intent is to issue an air quality AO authorizing the project with the following recommended
conditions and that failure to comply with any of the conditions may constitute a violation of the AO.

II.B REQUIREMENTS AND LIMITATIONS

II.B.1 Site-Wide Requirements
II.B.1.a The owner/operator shall not allow visible emissions from the following emission points to
exceed the following values:

A. All fabric filter baghouse exhaust stacks - 10%

B. All electrostatic precipitator exhaust stacks - 10%

C. All scrubber exhaust stacks - 10%

D. All incinerator exhaust stacks - 10%

E. All boiler exhaust stacks - 10%

F. All other points - 20%.

[R307-401-8]

II.B.1.a.1 Opacity observations of emissions from stationary sources shall be conducted according to 40
CFR 60, Appendix A, Method 9. [R307-401-8]

II.B.1.b The owner/operator shall not produce more than the following:

A. 12,000,000 troy ounces of gold per rolling 12-month period

B. 60,000,000 troy ounces of silver per rolling 12-month period

C. 400 tons of sweeps per rolling 12-month period.

[R307-401-8]

II.B.1.b.1 The owner/operator shall:

A. Determine gold, silver, and sweeps production by company production records

B. Record gold and silver production on a daily basis and record sweeps production
on a monthly basis

C. Use the gold and silver production data to calculate a new rolling 12-month total
by the 20th day of each month using data from the previous 12 months

D. Use the sweeps production data to calculate a new rolling 12-month total by the
20th day of January, April, July and October of each year using data from the
previous 12 months.

E. Keep the gold, silver, and sweeps production records for all periods the plant is
in operation.

[R307-401-8]

DAQE-IN103670029-24
Page 9

II.B.2 Baghouse Requirements
II.B.2.a The owner/operator shall use baghouses to control particulate emissions from the sweeps
preparation process, melt room furnaces, electric tilt furnaces, electric push-out furnaces, and the
ashing furnace. [R307-401-8]

II.B.2.b The owner/operator shall install a manometer or magnehelic pressure gauge to measure the static
pressure differential across each baghouse. [R307-401-8]

II.B.2.b.1 The pressure gauge shall be located such that an inspector/operator can safely read the indicator
at any time. [R307-401-8]

II.B.2.b.2 The pressure gauge shall measure the static pressure differential in 1-inch water column
increments or less. [R307-401-8]

II.B.2.c During operation of each baghouse, the owner/operator shall maintain the static pressure
differential within the range recommended by the manufacturer for normal operations.
[R307-401-8]

II.B.2.c.1 The owner/operator shall record the static pressure differential at least once per operating day
while each baghouse is operating. [R307-401-8]

II.B.2.c.2 The owner/operator shall maintain the following records of the static pressure differential:

A. Unit identification;

B. Manufacturer recommended static pressure differential range for the unit;

C. Daily static pressure differential readings;

D. Date of reading.

[R307-401-8]

II.B.2.d At least once every 12 months, the owner/operator shall calibrate each pressure gauge in
accordance with the manufacturer's instructions or replace the pressure gauge. [R307-401-8]

II.B.2.d.1 The owner/operator shall maintain records of each pressure gauge calibrations and replacements.
[R307-401-8]

II.B.3 Emergency Engine Requirements
II.B.3.a The owner/operator shall not operate the emergency engine on site for more than 100 hours per
rolling 12-month period during non-emergency situations. There is no time limit on the use of
the engine during emergencies. [40 CFR 63 Subpart ZZZZ, R307-401-8]

II.B.3.a.1 To determine compliance with a rolling 12-month total, the owner/operator shall calculate a new
12-month total by the 20th day of each month using data from the previous 12 months. Records
documenting the operation of the emergency engine shall be kept in a log and shall include the
following:

A. The date the emergency engine was used

B. The duration of operation in hours

C. The reason for the emergency engine usage.

[40 CFR 63 Subpart ZZZZ, R307-401-8]

DAQE-IN103670029-24
Page 10

II.B.3.b The owner/operator shall only use natural gas as fuel in the emergency engine. [R307-401-8]

II.B.4 Wet Scrubber Requirements
II.B.4.a The owner/operator shall use the following scrubbers to control the following process streams.

Scrubber Process Stream
Scrubber #248 silver anode slime washing process, silver nitrate plant, and slime
plant

Scrubber #359 gold electrolytic cells, gold refinery wet circuits, gold chloride
electrolytic production, silver chlorides sludge processing,
chlorination furnaces, melt furnaces, tilt furnaces, push-out
furnaces, and drying cabinets

Scrubber #760 wastewater treatment tanks and laboratory

Scrubber #761 silver electrolytic cells

All exhaust air from the above-mentioned process streams shall be routed through the indicated
scrubber before being vented to the atmosphere.

[R307-401-8]

II.B.4.b During operation of each scrubber, the owner/operator shall maintain both the pressure drop and
the liquid flow rate within the respective range recommended by the manufacturer for normal
operations. [R307-401-8]

II.B.4.b.1 The parameters shall be monitored with instruments located such that an inspector/operator can
safely read the output any time. [R307-401-8]

II.B.4.c The owner/operator shall record both the pressure drop and liquid flow rate at least once per
operating day while each scrubber is operating. [R307-401-8]

II.B.4.c.1 The owner/operator shall maintain the following records of the pressure drop and liquid flow
rate:

A. Unit identification;

B. Manufacturer recommended pressure drop and liquid flow rate range;

C. Daily pressure drop and liquid flow rate readings;

D. Date of reading.

[R307-401-8]

II.B.4.d At least once every 12 months, the owner/operator shall calibrate each instrument in accordance
with the manufacturer's instructions or replace the instrument. [R307-401-8]

II.B.4.d.1 The owner/operator shall maintain records of each instrument calibrations and replacements.
[R307-401-8]

II.B.4.e The owner/operator shall install a scrubber (ID# 761) that is certified to meet a NOx emission
reduction of no less than 24%. [R307-401-8]

II.B.4.e.1 To demonstrate compliance with the above condition, the owner/operator shall maintain records
of the manufacturer's emissions guarantee for the installed scrubber. [R307-401-8]

DAQE-IN103670029-24
Page 11

PERMIT HISTORY

This Approval Order shall supersede (if a modification) or will be based on the following documents:

Supersedes AO DAQE-AN103670028-17A dated May 15, 2017
Is Derived From NOI dated January 16, 2024

DAQE-IN103670029-24
Page 12

ACRONYMS

The following lists commonly used acronyms and associated translations as they apply to this document:

40 CFR Title 40 of the Code of Federal Regulations
AO Approval Order
BACT Best Available Control Technology
CAA Clean Air Act
CAAA Clean Air Act Amendments
CDS Classification Data System (used by Environmental Protection Agency to classify
sources by size/type)
CEM Continuous emissions monitor
CEMS Continuous emissions monitoring system
CFR Code of Federal Regulations
CMS Continuous monitoring system
CO Carbon monoxide
CO2 Carbon Dioxide
CO2e Carbon Dioxide Equivalent - Title 40 of the Code of Federal Regulations Part 98,
Subpart A, Table A-1
COM Continuous opacity monitor
DAQ/UDAQ Division of Air Quality
DAQE This is a document tracking code for internal Division of Air Quality use
EPA Environmental Protection Agency
FDCP Fugitive dust control plan
GHG Greenhouse Gas(es) - Title 40 of the Code of Federal Regulations 52.21 (b)(49)(i)
GWP Global Warming Potential - Title 40 of the Code of Federal Regulations Part 86.1818-
12(a)
HAP or HAPs Hazardous air pollutant(s)
ITA Intent to Approve
LB/YR Pounds per year
MACT Maximum Achievable Control Technology
MMBTU Million British Thermal Units
NAA Nonattainment Area
NAAQS National Ambient Air Quality Standards
NESHAP National Emission Standards for Hazardous Air Pollutants
NOI Notice of Intent
NOx Oxides of nitrogen
NSPS New Source Performance Standard
NSR New Source Review
PM10 Particulate matter less than 10 microns in size
PM2.5 Particulate matter less than 2.5 microns in size
PSD Prevention of Significant Deterioration
PTE Potential to Emit
R307 Rules Series 307
R307-401 Rules Series 307 - Section 401
SO2 Sulfur dioxide
Title IV Title IV of the Clean Air Act
Title V Title V of the Clean Air Act
TPY Tons per year
UAC Utah Administrative Code
VOC Volatile organic compounds

3/4/24, 9:00 AM State of Utah Mail - Legal Notice to be published March 3, 2024
https://mail.google.com/mail/u/0/?ik=b4fd0e1085&view=pt&search=all&permmsgid=msg-f:1792289466433189450&simpl=msg-f:1792289466433189450 1/1
Jeree Greenwood <[e-mail]>
Legal Notice to be published March 3, 2024
[e-mail] <[e-mail]>Thu, Feb 29, 2024 at 7:33 PM
To: Jeree Greenwood <[e-mail]>, "Salt Lake Tribune LaRee Whitmar - [e-mail]" <[e-mail]>
Hello Jeree,

Attached is the Order Confirmation, Run Date, Proof and Cost. The Legal Notice will publish on Sunday,
March 3rd 2024.

Thanks and I hope that you have a great rest of the week,

LaRee Whitmer
Senior Advertising Executive
The Salt Lake Tribune / The Moab Times-Independent
[e-mail] / P: 801.237.2990
[Quoted text hidden]
Order Confirmation, Run Date, Proof and Cost.pdf
138K

DAQE-NN103670029-24

February 29, 2024

Salt Lake Tribune and Deseret News
Legal Advertising Dept.
P.O. Box 704055
West Valley City, UT 84170
Acct #9001399880

RE: Legal Notice of Intent to Approve

This letter will confirm the authorization to publish the attached NOTICE in the Salt Lake Tribune and
Deseret News on March 3, 2024.

Please mail the invoice and affidavit of publication to the Utah State Department of Environmental
Quality, Division of Air Quality, P.O. Box 144820, Salt Lake City, Utah 84114-4820. If you have any
questions, contact Jeree Greenwood, who may be reached at [phone].

Sincerely,

{{$s }}

Jeree Greenwood
Office Technician

Enclosure

cc: Salt Lake County
cc: Wasatch Front Regional Council

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144820 • Salt Lake City, UT 84114-4820
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor

DEIDRE HENDERSON
Lieutenant Governor

Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF AIR QUALITY
Bryce C. Bird
Director

DAQE-NN103670029-24
Page 2
NOTICE

A Notice of Intent for the following project submitted in accordance with R307-401-1, Utah
Administrative Code (UAC), has been received for consideration by the Director:

Company Name: Asahi Refining USA, Incorporated
Location: Asahi Refining Incorpoarted – 4601 West 2100 South, West Valley City, UT
Project Description: Asahi Refining USA, Incorporated (Asahi) currently operates a precious metals
refinery in West Valley City, Salt Lake County. Mined doré and scrap are
melted and tested for purity using small electric induction furnaces and then
separated depending on gold and silver content. Separation is achieved by using
various inorganic chemicals and electrolytic methods. Silver is poured into
anode molds and then placed into the electrolytic cells. The cells contain silver
nitrate solution, and the low voltage current causes silver crystal to form onto a
cathode plate. The silver crystal is scraped off and collected.

Asahi has requested a modification to Approval Order
DAQE-AN103670028-17A to replace the silver electrolytic cells (Equipment ID
II.A.3 in Approval Order DAQE-AN103670028-17A). The NOx emissions from
the new silver electrolytic cells will be controlled with a new scrubber (Scrubber
ID 761). The scrubber currently servicing the existing silver electrolytic cells
(Equipment ID II.A.23 - Scrubber 760) will be retained and will continue to
control other, existing processes. The NOx and Sulfur dioxide emission
limitations outlined in the current Approval Order will not be increasing as part
of this modification. The new equipment will operate under existing emissions
limitations.

The completed engineering evaluation and air quality impact analysis showed the proposed project meets
the requirements of federal air quality regulations and the State air quality rules. The Director intends to
issue an Approval Order pending a 30-day public comment period. The project proposal, estimate of the
effect on local air quality and draft Approval Order are available for public inspection and comment at the
Utah Division of Air Quality, 195 North 1950 West, Salt Lake City, UT 84116. Written comments
received by the Division at this same address on or before April 2, 2024 will be considered in making the
final decision on the approval/disapproval of the proposed project. Email comments will also be accepted
at [e-mail]. If anyone so requests to the Director in writing within 15 days of publication of this
notice, a hearing will be held in accordance with
R307-401-7, UAC.

Under Section 19-1-301.5, a person who wishes to challenge a Permit Order may only raise an issue or
argument during an adjudicatory proceeding that was raised during the public comment period and was
supported with sufficient information or documentation to enable the Director to fully consider the
substance and significance of the issue.

Date of Notice: March 3, 2024

{{#s=Sig_es_:signer1:signature}}

Asahi Refining USA
Sources:Wastewater - wastewater treatment tanks Wastewater - wastewater treatment tanks
Silver refinery - Silver electrolytic cells Silver refinery - Silver electrolytic cells
Laboratory Laboratory
760 PTE Inlet PTE Inlet PTE Outlet PTE Inlet PTE Inlet PTE Outlet PTE Inlet PTE Inlet PTE Outlet
Pollutant (lb/hr)1 (tn/yr)1 (tn/yr)1 Pollutant (lb/hr)2 (tn/yr)2 (tn/yr)2 (lb/hr)2 (tn/yr)2 (tn/yr)2
HCl 7.498 32.842 0.657 HCl 7.498 32.842 0.657 0 0 0CL20.010 0.043 0.001 CL2 0.010 0.043 0.001 0 0 0
NOx 1.225 5.366 4.078 NOx 0.613 2.683 2.039 0.613 2.683 2.039
SO2 2.989 13.094 0.262 SO2 2.989 13.094 0.262 0 0 0
PM10 0 0.000 0 PM10 0 0 0 0 0 0
PM2.5 0 0.000 0 PM2.5 0 0 0 0 0 0
CO 0 0.000 0 CO 0 0 0 0 0 0
VOC 0 0.000 0 VOC 0 0 0 0 0 0
Assumptions:
1- Based at 100% hourly throughput for current permitted limit of 60,000,000 ozt Ag **about 1/2 of nox goes to 761**
2 - Projected increase based on source equipment distribution about 1/2 stays with 760
Scrubber inlet gas stream analysis (lb/hr) provided by J
8760 operating hours
S760 Current S760 Future S761 Future
ESR PJ - Equipment informaƟon for air permit renewal
11/27/2023 Akitoshi Matsumori
Revised on 1/16/2024 Akitoshi Matsumori
1. Project DescripƟon
Asahi would like to upgrade the electrolysis cells for silver refining due to the
equipment deterioraƟon. The new electrolysis cells are scheduled to be installed
in a new building (4601 West 2100 South, West Valley City, UT) currently under
construcƟon, and the commissioning is planned from October 2025. The
operaƟon of the exisƟng old electrolysis cells will be phased out from October
2025 onwards, and will be completely shut down once the new electrolysis cells
into full operaƟon.
Asahi also would like to apply for installing a new wet scrubber in the same
building as new electrolysis cells to control process gases containing contaminants
from that new electrolysis cells. The new scrubber should be installed by August
2025, in Ɵme for commissioning of the new electrolysis cells. The exisƟng
scrubber, Asahi internal name is scrubber 760, that controlled the old electrolysis
cells will not be removed and will conƟnue to be used as it conƟnues to control
other exisƟng equipment.
These equipment upgrades do not involve changes to the refining process itself
at Asahi. Furthermore, these equipment upgrades do not involve any significant
increase or decrease in Asahi's producƟon amount itself.
2. Material Processed
The material composiƟon processed by the new electrolysis cells is no different
from the convenƟonal material composiƟon. The silver material with a purity of
99.9% or less is set as an anode in the new electrolysis cells, and an
electrochemical reacƟon produces silver with a purity of 99.9% or more in the
new electrolysis cells. The electrolyte used is the same silver nitrate aqueous
soluƟon as before. Typical electrolytes have a pH of 1 to 3.
3. Proposed Equipment
As menƟoned in the project descripƟon secƟon, Asahi will apply for the
installaƟon of new electrolysis cells and new wet scrubber. When operaƟng, the
electrolysis cells will be a source of small amounts of nitrogen oxides (NOx).
Control of pollutants from the electrolysis cells will be achieved by a new wet
scrubber.
Table 1 shows the specificaƟon informaƟon of the new wet scrubber that Asahi
wants to apply. The specificaƟon sheet provided from the manufacturer is
included as Appendix A.
Table 1: Outline of the specificaƟon of the new wet scrubber
Manufacturer Tri-Mer corporaƟon
Model # V/F-108-120
Equipment name VerƟcal Packed Bed Scrubber System
Asahi Internal name Scrubber 761
This wet scrubber system will be installed on the exhaust downstream from the
proposed electrolysis cells. The process gas exhausted to the wet scrubber is
scrubbed with a causƟc soda soluƟon and then exhausted to the outside of the
building through the stack. The final height of the stack will be about 51 Ō from
the ground level. The breakdown of the height is the following.
New building height will be 38.7 ~ 39 Ō.
Scrubber stack height will be 18 Ō. This stack will be put on the roof where
the roof height is about 39 Ō.
Table 2 shows the overview of the expected scrubber operaƟng condiƟons.
Please refer to Appendix A and B for the details.

Table 2: Expected scrubber operaƟng condiƟons (EsƟmaƟon)
Chemicals used CausƟc soda
EsƟmated control pH range > 9
*1
EsƟmated control recirculaƟon flow rate range > 540 gpm
*1
EsƟmated control DP*2 range at mist eliminator 1.6 water inches*1
EsƟmated control DP*2 range at packing bed 2.8 water inches*1
Control conducƟvity range TBD*3
*1) Based on the manufacturer recommendaƟons (See Appendix B).
*2) DP = DifferenƟal Pressure
*3) The conducƟvity level should be such that the salts in soluƟon don’t precipitate. (See
Appendix B)
4. Process flow diagram
A process flow diagram is included as Figure 1.
5. Facility aerial
A facility aerial is included as Figure 2.
6. Remarks
If this applicaƟon is applied, Asahi will have four wet scrubbers. Table 3
suggests the relaƟonship between the equipment/process and the control wet
scrubber. The exisƟng scrubber, Asahi internal name is scrubber 760, that
controlled the old electrolysis cells will not be removed and will conƟnue to be
used as it conƟnues to control other exisƟng equipment.

Table 3;
RelaƟonship between the equipment/process and the control wet scrubber
Item #
in AO
Equipment/Process name
in AO
ExisƟng wet scrubber New wet
scrubber
Scrubber
359
Scrubber
248
Scrubber
760
Scrubber
761
2 Wastewater treatment ×
3 Old electrolyƟc cells (Silver) ×
(by Oct 2026)
New electrolysis cells (Silver) ×
(from Oct 2025)
4 ElectrolyƟc cells (Gold) ×
5 Wet Circuit (Gold) ×
6 ChlorinaƟon ×
7 Slime washing ×
8 Wet Chlorides Treatment ×
13 ChlorinaƟon Furnaces ×
15 Tilt Furnaces ×
16 Push-out Furnaces ×
19 Nitrate Plant ×
21 Drying Cabinet ×
25 Tank System ×

Old electrolysis cells
(Silver Refining)
New electrolysis cells
(Silver Refining)
Refined Silver
(Ag > 99.9%)
NOx gas
Wet scrubber
(Scrubber 760)
Silver material
(Ag < 99.9%)
ExisƟng ƟlƟng
furnace
Silver anodes
(Ag < 99.9%)
New wet scrubber
(Scrubber 761)
NOx gas
Refined Silver
(Ag > 99.9%)

ExisƟng building
New building
Commissioning will
be started from Oct
2025.
OperaƟon will be
phased stopped
aŌer Oct 2025.
Outside
building
Outside
building
Figure 1: Process Flow Diagram (Upgrading the electrolysis cells and wet scrubber)

Figure 2: Facility aerial (Referred by Google Earth©)
Appendix A
Technical specificaƟon sheet of new wet scrubber
Corporate Office
1400 E Monroe St
PO Box 730
Owosso, MI 48867
Main [phone]
Fax [phone]

Kirk Kelley Technical Specification R3
Sales Engineer, Wet Scrubber Technologies December 14, 2023
Mobile [phone] [e-mail]
[e-mail] www.tri-mer.com

Technical Specification
V/F-108-120, Vertical Packed Bed Scrubber System

Prepared for:
Asahi Refining
4601 W. 2100 S
Salt Lake City, UT

Attention: Joshua Zannoni
Phone: [phone]
Email: [e-mail]

Asahi Refining Technical Specification R3 December 14, 2023

Page 2 of 3
I. Operating Conditions and Design Parameters (items bolded in specification are critical parameters)
A. Process description ............................................ NO2, SO2, HCl, Cl2 from precious metal recovery process
B. Process outlet flow, acfm at 70°F ..................................................................................................... 30,000
C. Process contaminant loads or concentrations at inlet:
1. NO2 ..................................................................................................................................... 49.0 lb/hr
2. SO2 ..................................................................................................................................... 1.30 lb/hr
3. HCl ........................................................................................................................................ 7.0 lb/hr
4. CI2 ....................................................................................................................................... 32.0 lb/hr
D. External static pressure..................................................................................................................... -6.0 "wg
E. Tri-Mer system internal static pressure, "wg ...................................................................................... -4.0 “wg
F. Total estimated process pressure, "wg ............................................................................................ -10.0 “wg
G. Environmental conditions:
1. Geographic location .............................................................................................. Salt Lake City, UT
2. Elevation, feet above sea level .............................................................................................. ≈ 4,265
3. Equipment location (i.e., indoors or outdoors) .................................................................... Unknown
II. System Component Specifications
A. Vertical/Flow (V/F) Packed Bed Tower Scrubber: Model V/F-108-120
1. Scrubber material of construction ................................................. UV-inhibited white polypropylene
2. Packing type ..................................................................................................................... Tri-Packs®
3. Packing material of construction .................................................................................. polypropylene
4. Scrubber Diameter ...................................................................................................................... 108”
5. Packed Bed Depth ...................................................................................................................... 120”
6. Scrubber wall thickness ............................................................................................................... 1/2”
7. Packing Quantity ....................................................................................................... 640 Cubic Foot
8. Mist eliminator type ....................................................... chevron blade, 99.0% efficiency at ≥ 20 µm
9. Mist eliminator material of construction........................................................................ polypropylene
10. Recirculation pump delivery ............................................................................................ 600 GPM
11. Recirculation pump type ........................................................ centrifugal, horizontal, magnetic drive
12. 100% redundant recirculation rumps ....................................................................................Included
13. Plumbing ................................................................................................................ schedule 80 PVC
14. Recirculation sump................................................................................. integral/internal to scrubber
15. pH of recirculation pump ........................................................................................................ 9-9.5

Asahi Refining Technical Specification R3 December 14, 2023

Page 3 of 3
III. Performance Guarantee
A. Removal of NO2 (caustic only) ......................................................................................................... 24.00%
B. Removal of SO2 .................................................................................................................................... 99.5%
C. Removal of HCl ................................................................................................................................... 99.99%
D. Removal of Cl2 .................................................................................................................................... 99.80%

IV. Consumables and Specified Operational Minimums (estimation)
A. 50% NaOH .......................................................................................................................................... 1.9 gph
B. Evaporation ....................................................................................................................................... 39.2 gph
C. Electrical Power ................................................................................................................................. 73.7 kW
D. Plant Water ..................................................................................................................................... 127.2 gph
E. Liquid Waste ..................................................................................................................................... 90.0 gph
V. Pressure Drop Minimums/Maximums
A. Mist Eliminator, “wg .............................................................................................................................. 0.6/1.6
B. Packing Media, “wg .............................................................................................................................. 1.8/2.8

Appendix B

Recommended operaƟon condiƟons by
manufacturer

Allow sender | Block sender
From:Joshua Zannoni
To:Akitoshi Matsumori
Subject:Fwd: Tri-Mer Proposal P-22.895 R9
Date:Wednesday, November 22, 2023 8:04:07 AM
Attachments:image002.png
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Aki,
Please see below for Tri-Mers response to our questions.
From: Kirk Kelley <[e-mail]>
Sent: Wednesday, November 22, 2023 6:36:17 AM
To: Joshua Zannoni <[e-mail]>
Subject: RE: Tri-Mer Proposal P-22.895 R9
Caution! This message was sent from outside Asahi. Do not click links or attachments unless you recognize and trust the sender.
Joshua,
The answers to your questions are below:
The design recycle rate is about 1.1 times the minimum rate. So the minimum would be 540 gpm.
The pH of 9.0 is a minimum. Higher levels are acceptable, but you should not exceed pH 12. The removal efficiency will be the pretty much the same between those ranges.
The conductivity level should be such that the salts in solution do not precipitate.
The specific surface area for 2-inch Tri-Packs is 48 ft2/ft3.
The proposal includes a VFD for the exhaust fan, but the recirculation pumps are controlled by a line starter.
Just to let you know, we will be closed for the Holiday weekend starting at 3:00 p.m. EST today. We will reopen on Monday. If you have any additional questions throughout that
time, I will still be checking my emails.
Have a safe and Happy Thanksgiving Joshua.
Thanks,
Kirk KelleySales EngineerTri-Mer CorporationEmail: [e-mail]: 989-723-78381400 E Monroe St,Owosso MI, 48867
www.tri-mer.com
From: Joshua Zannoni <[e-mail]>
Sent: Monday, November 20, 2023 11:47 AM
To: Kirk Kelley <[e-mail]>
Subject: RE: Tri-Mer Proposal P-22.895 R9
Kirk,
Thank you for the information. Can you provide some clarification around the items below:
Recirculation pump Is the recirculation pump's circulation flow rate of 600 gpm the maximum flow rate? Or is it the minimum flow rate?
(We need to know the minimum flow rate.)
pH of recirculation pump Is the range from 9 to 9.5 correct?
Is gas removal performance guaranteed even if the pH is higher than this range? Or does increasing the pH improve the removal performance?
Conductivity Are there any conductivity control standards recommended?
Packing condition
(liquid-gas interfacial area)What is the expected interfacial area (m2/tower)?
Others Are the scrubber fans and circulation pumps controlled by an inverter (VFD)?
Joshua Zannoni | Senior Process Engineer
A: Asahi Refining USA, Inc. | 4601 W 2100 S | Salt Lake City, UT 84120
E: [e-mail] | W: https://www.asahirefining.com
O: [phone] | M: [phone]
From: Kirk Kelley <[e-mail]>
Sent: Monday, November 20, 2023 6:40 AM
To: Joshua Zannoni <[e-mail]>
Subject: RE: Tri-Mer Proposal P-22.895 R9
Good Morning Joshua, Please see the attached “Technical Specification”. If there is something that you want us to add, please feel free to let us know. Thanks, Kirk Kelleysophospsmartbannerend